DESCRIPTION: (Applicant's Abstract) Since 1978, a longitudinal study has been underway investigating, in a low risk population, the effects of marijuana and cigarettes used during pregnancy. The overall purpose of this Ottawa Prenatal Prospective Study (OPPS) is to examine the effects of these drugs on pregnancy, the neonate and the pre-school and school aged offspring. The general objective of this competitive renewal is to determine whether developmental sequelae and behavioral difficulties observed in the OPPS subjects, statistically associated in a differential fashion with prenatal marijuana and cigarette exposure, persist in the adolescent (13-15 year old) and whether, by an in depth neurobehavioral assessment, a greater degree of specificity of dysfunction can be identified. Because of the longitudinal nature of this OPPS, the predictive validity of the infant and early childhood tests can also be examined as can the continuity of effects over age. The neurobehavioral battery will focus upon those behaviors which we have identified to be vulnerable to the drugs in question with an emphasis upon facets of behavior that have been noted in the currently funded period examining 9 1/2 -12 year olds i.e. an association between in utero marijuana exposure and specific aspects of executive function and an association between in utero cigarette exposure and impaired performance in phonological aspects of language/reading, cognition and forms of perceptual processing involving attention to detail. The assessment will include an examination of memory, attention, strategic planning, aspects of language and reading, complex problem solving and the differential processes involved in the perceptual analysis of configural versus detailed aspects of stimuli. A distinction will also be made between the capabilities in basic content domains versus competency in the on-line integration of such material that is required prior to being able to perform executive function tasks. Behavior, sexual development and an assessment of both cigarette smoking and exposure to second hand smoke (using urine analysis and questionnaires) will also be evaluated in the adolescents. Maternal variables (e.g. health, nutrition, parity, education, age, other drugs, intelligence, personality) and postnatal, environmental variables will be included in multivariate statistical analysis. The OPPS is the only work to have published data on marijuana users' offspring beyond early childhood and is the most comprehensive longitudinal work examining school age children of cigarette smokers. The testing of children at mid-adolescence is particularly critical as the identification of subtle learning difficulties is most likely to manifest themselves when complex behaviors requiring focused attention and cognitive skills, normally present at this stage of development, can be examined in depth.